About

Zhenyun Qian is an Associate Research Professor in the Department of Electrical and Computer Engineering at Northeastern University. He received his B.S. degree in Electronic Science and Engineering from Southeast University in Nanjing, China, in 2011, and his M.S. and Ph.D. degrees in Electrical and Computer Engineering from Northeastern University in Boston, MA, in 2013 and 2017, respectively. His research interests include piezoelectric and thermo-mechanical transducers, 2D materials enhanced NEMS devices, low-power and zero-power sensors, MEMS-based optical switches, and flexible electronics. He has published more than 40 papers in the field of MEMS/NEMS and has been recognized with awards such as the Outstanding Paper Award at the 18th International Conference on Solid-State Sensors, Actuators and Microsystems and the Best Paper Award at the 2017 European Frequency and Time Forum & International Frequency Control Symposium. He has also contributed to multiple patents related to zero-power sensing technology and microelectromechanical devices, and has been involved in research projects funded by DARPA and NSF, focusing on ultra-small, high-resolution infrared sensors and wireless sensors for various applications.

Research topics

• Physics
• Materials science
• Optoelectronics
• Acoustics
• Engineering
• Electrical engineering
• Computer Science
• Composite material
• Nanotechnology
• Chemical engineering
• Electronic engineering
• Algorithm
• Condensed matter physics
• Optics
• Chemistry
• Nuclear magnetic resonance
• Chromatography
• Organic chemistry

Selected publications

• Vacuum-Packaged 30%-Doped ScAlN Resonators With AlN Absorbers for IR Spectroscopy

  Journal of Microelectromechanical Systems · 2026-02-13

  article

  This paper presents a high-performance infrared sensor based on a Scandium Aluminum Nitride (ScAlN) laterally vibrating resonator integrated with plasmonic absorbers for spectrally selective IR absorption. The proposed technology enables fast, compact, and high-resolution IR detection, making it ideal for the implementation of mobile gas-spectroscopy systems for environmental monitoring over large areas for extended periods. The sensor was designed to exhibit high IR absorptance at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.5~\mu $</tex-math> </inline-formula>m, matching the absorption peak of N<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O. The resonant sensor experimentally shows an outstanding mechanical quality factor (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q_{m}$</tex-math> </inline-formula>) of 2000, a 2.7% electromechanical coupling (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k_{t}^{2}$</tex-math> </inline-formula>), a high responsivity of 0.9 Hz/nW, a fast response of 6 ms and a low NEP of 320 pW/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm {Hz}^{1/2}$</tex-math> </inline-formula>. While we focus on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.5~\mu $</tex-math> </inline-formula>m in this system, the absorption wavelength is lithographically tunable, enabling the fabrication of multi-gas sensors on the same chip without using additional masks. A key innovation in this work compared to prior resonant IR detectors is the use of a novel material stack: Aluminum Nitride (AlN) as the dielectric in the Metal–Insulator–Metal plasmonic absorbers, combined with 30%-doped Scandium Aluminum Nitride (ScAlN) for the acoustic resonant cavity. This combination enhances sensor performance by taking advantage of the higher thermal resistance of ScAlN, as well as the higher temperature coefficient of frequency (TCF) of AlN compared to silicon dioxide (SiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>). SiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is traditionally used for IR absorption due to its optical properties; however, it is also characterized by a positive TCF, thereby degrading the thermal response of the resonator. In this work, the influence of geometrical parameters is experimentally investigated in hundreds of devices. The effect of tethering configurations and anchors’ width-to-length ratios on the sensor’s quality factor, thermal isolation, time response, and TCF is reported. Following optimization, the best-performing sensors are vacuum-packaged to enhance thermal isolation and improve response to IR. The device’s IR response is tested both in open-loop configuration with a vector network analyzer and in closed-loop within an oscillator circuit optimized for reduced phase noise. [2025-0145]

  PublisherDOI

• High-precision photonic neural networks utilizing microring resonators

  2025-02-17

  article

  Photonic neural networks (PNNs), due to its advantages of low latency, low power consumption, and high parallelism, hold promise in addressing the current bottlenecks faced by electronic computing hardware. However, constrained by the errors associated with analog computations, the computational precision of PNN architectures cannot rival that of electronic computing. Traditional methods for improving computational precision often necessitate the assistance of peripheral control circuits and algorithms, which can undermine the low-power consumption advantage of optical computing. In this work, we propose a method to enhance the computational precision of a photonic neural network system. By altering the coupling coefficient of the micro-ring resonator (MRR), we can improve the extinction ratio (ER) of the device, thereby increasing the dynamic range of weight adjustment. Simulation results on system computational precision indicate that increasing the ER of the devices can effectively elevate the effective number of bits for weighting. Additionally, MRR devices with high ER exhibit greater robustness against power noise.

  PublisherDOI

• Palladium-Coated Laterally Vibrating Resonators (LVRs) for Hydrogen Sensing

  2025-10-19

  article

  This work presents a novel hydrogen sensor based on 30 % scandium-doped aluminum nitride (ScAlN) laterally vibrating resonators (LVRs) functionalized with a palladium (Pd) thin film. The micro-electro-mechanical system (MEMS) device operates by detecting shifts in resonant frequency resulting from hydrogen absorption in the Pd layer. The sensor demonstrates a high mechanical quality factor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(Q_{m})$</tex> of 820, an electromechanical coupling coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(k_{t}^{2^{-}})$</tex> of 3.18 %, and an enhanced responsivity of 26 Hz/ppm in the low-parts-per-million (ppm) range, making it highly suitable for hydrogen leak detection. Compared to existing MHz-range technologies, the sensor achieves up to 50x higher sensitivity, while also offering multi-frequency definition in a single lithographic step, minimal footprint, and the highest quality factor among comparable miniaturized platforms.

  PublisherDOI

• Palladium-Coated Laterally Vibrating Resonators (LVRs) for Hydrogen Sensing

  ArXiv.org · 2025-09-02 · 1 citations

  preprintOpen access

  This work presents a novel hydrogen sensor based on 30% scandium-doped aluminum nitride (ScAlN) laterally vibrating resonators (LVRs) functionalized with a palladium (Pd) thin film. The micro-electro-mechanical system (MEMS) device operates by detecting shifts in resonant frequency resulting from hydrogen absorption in the Pd layer. The sensor demonstrates a high mechanical quality factor (Qm) of 820, an electromechanical coupling coefficient (kt2) of 3.18%, and an enhanced responsivity of 26 Hz/ppm in the low-parts per million (ppm) range, making it highly suitable for hydrogen leak detection. Compared to existing MHz-range technologies, the sensor achieves up to 50x higher sensitivity, while also offering multi-frequency definition in a single lithographic step, minimal footprint, and the highest quality factor among comparable miniaturized platforms.

  PublisherOA PDFDOI

• Enhanced Infrared Sensing With 30% Scandium-Doped Aluminum Nitride Acoustic Delay Lines Integrated with Metamaterial Absorbers

  2024-09-22

  article

  This work introduces a novel type of infrared (IR) sensor that enhances sensitivity by pairing plasmonic absorbers with Lamb Wave Acoustic Delay Lines (ADLs). This technique allows for the expansion of the absorber’s area beyond the constraints of the device’s geometry, providing additional degrees of freedom to further optimize IR sensing performance. The device achieved an IR absorption of approximately 90% at a wavelength of 4.6 µm and exhibited a substantial frequency shift of 23.84 kHz, reflecting a large absorber area of 0.081 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> when exposed to 29.59 µW of incident IR power. Moreover, by replacing Aluminum Nitride (AlN) with highly doped Scandium Aluminum Nitride (ScAlN) in the resonant cavity of the delay line, we achieved a high temperature coefficient of frequency (TCF) of -53 ppm/°C and a large thermal resistance, leveraging ScAlN’s superior thermal properties. This design resulted in a high responsivity of 806 Hz/µW, outperforming our latest resonator-based IR sensor, which utilized a material stack featuring AlN as the dielectric in Metal-Insulator-Metal (MIM) plasmonic absorbers and 30%-doped ScAlN in the resonant cavity to enhance the TCF [1]. The results of this study demonstrate the potential of ScAlN ADLs to advance toward uncooled, miniaturized, and highly sensitive IR sensors.

  PublisherDOI

• HIGH-QUALITY FACTOR, HIGH TCF SCANDIUM ALUMINUM NITRIDE MEMS RESONATOR FOR LOW-NOISE INFRARED SENSING

  2024-06-02

  articleOpen access

  This paper reports on the demonstration of a groundbreaking, high-sensitivity gas sensor based on a Scandium Aluminum Nitride (ScAlN) MEMS resonator integrated with plasmonic absorbers for spectrally selective IR sensing.The device achieved 75% absorptance at 4.5 m, a mechanical quality factor (Qm) approaching 2000, and an electromechanical coupling ( 2 ) of 2.7%.To the best of our knowledge, such a high Q had never been demonstrated before for ScAlN MEMS resonators with bottom interdigitated electrodes (allowing absorber integration on the top).Moreover, we showcased a notable advancement by adopting a novel material stack: AlN as the dielectric material for the Metal-Insulator-Metal (MIM) plasmonic absorbers, coupled with 30%-doped ScAlN for the resonant cavity.This strategic choice significantly improved the sensor's sensitivity, doubling it compared to previous implementations, by boosting both the device's Temperature Coefficient of Frequency (TCF) and its thermal resistance, leveraging ScAlN's superior thermal properties over AlN.

  PublisherDOI

• Parametric frequency comb generator based AlScN MEMS IR detector for low-power and high-performance applications

  2024-06-07 · 2 citations

  article

  This article addresses the imperative of reducing the limit-of-detection (LoD) in sensing systems, focusing on micro- and nanoelectromechanical (MEM/NEM) resonant technologies. Typically, advancements on MEM/NEM offer high sensitivity and electromechanical performance, which is crucial for achieving quantum-limited LoD. However, when these devices are integrated in closed-loop oscillator, frequency fluctuations are introduced due to electrical noise, degrading the LoD. This work proposes a novel sensing system for Aluminum Scandium Nitride (AlScN) microacoustic resonant infrared (IR) detectors that addresses these challenges. Moreover, it enables self-sustained oscillation states without active components, while consuming minimal power (∼10 mW) and limiting RF power dissipation (≤ 1 µW), thus shaping a new paradigm in sensing technology.

  PublisherDOI

• Experimental Demonstration of a Plasmonically-Enhanced Vacuum-Packaged LVR-Based Gas Sensor

  2024-09-22

  article

  This work proposes the combination of a microelectromechanical system (MEMS)-based spectrally-selective uncooled thermal infrared (IR) detector with an IR spectroscopic multipass gas cell to enable new applications like the remote monitoring of the concentration of atmospheric trace gas molecules through direct laser absorption spectroscopy (LAS) on novel sensing platforms such as drones. In particular, due to its increasingly concerning impact as a greenhouse gas, N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O was selected as the target molecule for this experimental demonstration, and a final sensitivity of around 5.4 Hz/ppm was assessed. The enabling technology consists of a 30% doped ScAlN laterally vibrating resonator (LVR) integrated with spectrally selective metal-insulator-metal (MIM) plasmonic metamaterial absorbers. After being vacuum packaged, it has been experimentally characterized, resulting in a responsivity of 0.3 Hz/nW and a NEP of 500 pW/Hz<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup>. These performances exceed by more than two times and a half the ones of the same LVR without absorbers, thus demonstrating the potential improvements that this approach can lead to.

  PublisherDOI

• Metasurface-Enhanced Micromechanical Photoswitch for Zero Power Human Presence Sensing

  IEEE Sensors Letters · 2023-08-10 · 2 citations

  article

  This letter reports on zero standby power human presence detectors based on an optimized micromechanical photoswitch (MP) with a metasurface-enhanced long wavelength infrared (LWIR) absorber, increased thermal sensitivity, reduced bias voltage, and a wide field-of-view. The reported device shows the capability of detecting a human body around 2.65 m and human hand around 1 m distance using low bias voltages without using any focal lenses. Existing wireless motion detectors based on pyroelectric IR sensors consume ∼100 μW power on standby continuously and produce frequent false alarms due to nonrelevant objects (such as moving cars and falling leaves), which inevitably drains the battery in a relatively short period of time (typically less than a year). The demonstrated zero-power sensor here exploits the LWIR energy emitted from a human body for true presence detection without consuming any electrical power on standby. The first experimental demonstration of human body detection with vacuum packaged MP at a distance comparable to commercial motion detectors is enabled by the optimization of an MP in terms of thermomechanical performance (thermal sensitivity ∼1.5 nm/nW, stiffness ∼0.2 nN/nm, and threshold ∼10 nW) and IR absorption (η > 60% in λ = 6–14 μm, field-of-view ∼110°). The new broadband LWIR metasurface absorbers improve the structural symmetry of MP by matching the material stacks of reflecting and absorbing heads. This improvement allows the MP to work with lower voltage bias, thus making it compatible with low-power electronics.

  PublisherDOI

• Thermomechanical Modeling and Optimization of Zero-Power Micromechanical Photoswitch

  Journal of Microelectromechanical Systems · 2022-02-09 · 5 citations

  article

  This paper presents an in-depth thermomechanical analysis of zero-power micromechanical photoswitches (MPs) aiming at aggressive performance enhancement for applications that require ultralow infrared (IR) detection threshold. An accurate analytical model was first derived and used to maximize the thermal sensitivity of the MPs through a loop-based optimization program. With specific pre-defined boundary conditions, such a program can be used to generate a set of device geometrical parameters leading to highest possible thermal sensitivity without sacrificing the structural strength of the device (i.e., spring constant), which otherwise will have to be done with time-consuming numerical simulations. The optimized MPs show more than 4 times improvement in thermal sensitivity compared to previous demonstrations, thanks to the high thermal resistance and temperature sensitivity achieved using the thermomechanical model. The demonstrated theoretical analysis and thermomechanical optimization methods for the MPs are critical for the development of the next-generation zero-power IR sensors specifically designed for applications that require ultra-sensitive IR detection capability without compromising their sensor size, weight and power consumption. [2021-0231]

  PublisherDOI

Frequent coauthors

• Matteo Rinaldi

  Scuola Normale Superiore

  98 shared

• Sungho Kang

  Yonsei University

  56 shared

• Vageeswar Rajaram

  Northeastern University

  54 shared

• Sila Deniz Calisgan

  Northeastern University

  30 shared

• Antea Risso

  22 shared

• Cristian Cassella

  Universidad del Noreste

  20 shared

• Yu Hui

  20 shared

• N.E. McGruer

  15 shared

Awards & honors

• Outstanding Paper Award at the 18th International Conference…
• Best Paper Award at the 2017 European Frequency and Time For…
• DARPA Riser 2018
• Chinese Government Award for Outstanding Self-financed Stude…
• Patent for Zero-Power Sensing Technology